Liquid hydrocarbon fuels

ABSTRACT

Liquid hydrocarbon fuels containing, in an amount sufficient to impart good detergent properties, an acetal produced by the reaction of a partial ester of an alcohol and an aldehyde, in which the ester has a least 18 carbon atoms.

Andress, Jr. et al.

[ 1 LIQUID HYDROCARBON FUELS [75] Inventors: Harry J. Andress, .Ir., Pitman;

Henry Aslriian, East Brunswick,

both of NJ. [73] Assignee: Mobil Oil Corporation, New York,

[22] Filed: Sept. 8, 1972 [21] Appl. No.2 287,316

[52] US. CL... 44/63, 44/66, 44/70 [51] Int. Cl C101 1/18 [58] Field of Search 44/63-66 [56] References Cited UNITED STATESPATENTS 2,237,660 4/1941 Ellis 44/70 May 21, 1974 Primary ExaminerDaniel E. Wyman Assistant Examiner-Mrs. Y. H. Smith Attorney, Agent, or Firm-Andrew L. Gaboriault; Raymond W. Barclay; Benjamin I. Kaufman [5 7 ABSTRACT Liquid hydrocarbon fuels containing, in an amount sufficient to impart good detergent properties, an acetal produced by the reaction of a partial ester of an alcohol and an aldehyde, in which the ester has a least 18 carbon atoms.

10 Claims, N0 Drawings Arundale et al. 44/63 I 1 LIQUID HYDROCARBON FUELS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to liquid hydrocarbon fuels and, in one of its aspects, relates more particularly to liquid. hydrocarbon fuels, which are normally susceptible of forming undesirable carburetor and intake valve deposits ininternal combustion engines and to a novel additive for effecting reduction of such deposits.

2. Description of the Prior Art It is well known to those skilled in the art that liquid hydrocarbon fuels, such as gasoline, and fuel oils, tend, on combustion, to form undesirabledeposits on carburetor and intake valves in internal combustion engines. The formation of such deposits tends to impair engine efficiency and often results in breakdown, necessitating cleaning operations and, in many instances, costly replacement of engine parts. This situation is particularly encountered in the use of modern liquid hydrocarbon fuels such as gasoline, jet fuel, diesel fuel and other fuels normally employed in the operation of internal combustion engines. Accordingly, a means for reducing or preventing the formation of such deposits in internal combustion engines represents a long-felt need.

SUMMARY OF THE INVENTION -of forming undesirable carburetor and intake valve deposits in internal combustion engines. A field of specific applicability is the improvement of liquid hydrocarbon fuels boiling from about 75F. to about 750F., including gasoline, jet fuel and diesel fuel'. 'Of particular significance is the treatment of petroleum distillatefuels having an initial boiling point of about 75F. to about 135F. and an end boiling point from about 250F. to about 750F. It shouldbe noted, in this respect, that the term distillate fuels or distillate fuel oils" is not intended to be restricted to straight-run distillatefractions. These distillate fuel oils can comprise straight-run distillate fuel oils, catalytically or thermally cracked (including hydrocracked) distillate fuel oils or mixtures of straight-run'distillate fuel oils, naphthas and the like, with cracked distillate stocks, More over, such fuel oils can be treated in accordance with wellknown commercial methods such as acid or caustic treatment, hydrogenation, solvent refining, clay treatment and the like.

The distillate fuels are characterized by their relatively low viscosity, pour point and the like. The principle property which characterizes these hydrocarbons, however, is their distillation range. Ashereinbefore indicated, this range will lie between about 75F. and about 750F. Obviously, the distillation range of each individual fuel will cover a narrower boiling range, falling, nevertheless, within the above-specified limits. Likewise, each fuel will boil substantially continuously throughout its distillation range.

Particularly contemplated among the fuels or fuel oils are Nos. 1, 2 and 3 fuel oils, used in heating and as diesel fuel oils, gasoline and jet combustion fuels as previously indicated. The domestic fuel oils generally confon'n to the specifications set forth in ASTM specification D396-48T. Specifications for diesel fuels are defined in ASTM specification D975-48T. Typical jet fuels are defined in military specification MIL-F-S 6248. In addition, as hereinbefore indicated, fuel oils of varying viscosity and pour points falling both within and outside the indicated ranges may also be effectively treated through the use of the novel additives of the present invention.

In general, the aforementioned acetals are employed in .the liquid hydrocarbon fuel in a minor amount. For most operations, this additive is employed in an amount from about 0.001 to about 10 percent and preferably in an amount from about 0.01 to about 0.5 percent, by weight, of the total weight of the fuel.

The" novel acetals of the present invention are prepared, as hereinbefore indicated, by the reaction of a partial ester of'an alcohol and an aldehyde, in which the ester has at least 18 carbon atoms. In general, the reaction is carried out at a temperature from about 75C. to about 200C. and preferably from about 125C. to about 175C. To promote the reaction an acidic catalyst is advantageously employed. For this purpose, various types of acidic catalysts may be employed such as sulfonic acid, paratoluene sulfonic acid, acidic clays, nitric acid, hydrochloric acid, alkylbenzene sulfonic acids, arylbenzene sulfonic acids, benzene sulfonic acid and alkane sulfonic acids. (others?) In general, it is found-that unless the above-described partial ester has at least 18 carbon atoms, the resulting acetal is ineffective in preventing undesirable formation of carburetor and intake valve deposits in internal combustion engines.

DESCRIPTION OF SPECIFIC EMBODIMENTS The following specific examples and comparative data will serve to illustrate the novel fuel compositions of the present invention and the efficacy of the abovedescribed acetals, as fuel additives, in reducing the formation of carburetor and intake valve deposits in internal combustion engines. 1

Example 1 A mixture of 134 grams (1 mol) trirnethylolpropane,

v282 grams (l mol) oleic acid, 3 grams para toluene sulcrnoocigHar crncmcmo Example 2 C1110 Cart W "cmbeiaig.

CH CH: -CH2 0 0 0191135 CHaCH: CH7OO 0131135 H: 0 CH1 0 Hz The above-prepared acetals of Examples 1 and 2 were next blended in a fuel composition comprising a gasoline containing 40 percent, by volume, catalytically cracked component, 40 percent catalytically re-- formed component and percent alkylate of approximately 904l0F. boiling range. The base fuel and the same fuel containing the acetals of Examples 1 and 2, respectively, were subjected to the following carburetor detergency test:

The deposit-forming tendencies of a fuel are determined in an 8 hour engine test. This accelerated test,

when run on fuels that contain no detergents, produces an amount of deposit equivalent to the amount observed in 4,000 miles of operation in field tests on taxicab fleets. A six-cylinder Chevrolet engine is equipped with notched rings to increase the amount of blowby. Engine is operated for 8 hours, using the fuel under test, at alternate idle and running cycles. In the idle cycle, the engine is run at idling speed of 400 rpm. with no load, for 5 minutes. Then, for one minute, the engine is run at a speed of 2,500 r.p.m. under a load of I B.H.P. and a 9.4 in mercury manifold pressure. During the running cycle, the blowby and part of the exhaust are released into the carburetor air intake during the idling cycle. After 8 hours operation at alternate run and idle, the carburetor is examined and rated as to the amount of deposit in the throttle throat. In the rating scale, a rating of 0 (zero) indicates a clean carburetor; 1=trace deposits, 2=light deposits; 3=medium deposits; and 4=heavy deposits.

The results obtained are shown in the following Table I:

TABLE I Carburetor Detergency Test in Gasoline Eight Hour Test with Pyrex Throttle Body Cone. lbs/ Detergency Composition 1000 bbls. Rating Base fuel 0 4.0

do. Ex. 1 50 1.2 do. Ex. 2 50 2.0

As will be seen from the foregoing comparative data of Table I, a marked improvement in reduction of carbonaceous carburetor deposits is achieved through the use of the acetals of the present invention.

The above-prepared acetal of Example 1 was next blended in a fuel composition comprising a full boiling range catalytically cracked gasoline containing 3cc. per gallon of tetraethyl lead. The resulting respective fuel compositions were then individually evaluated for their degree of improvement in reducing formation of carbonaceous surface deposits, employing the following intake valve deposit test:

The test is conducted in a Chevrolet 11 automobile with a 230 cu. in. engine on the outdoor rolls connected to a dynamometer. The cylinder head is overhauled for each run. The intake valves are weighed, numbered, and always used in the same cylinder. All tests are made with the second compression ring gap increased to 0.03 inch and with a special PVC PCV' New oil and test fuel are flushed through the respective systems.

A continuous 60 hour running period is comprised of repetitive cycles of 40 sec. at idle (500550 rpm) and sec. at 2000 rpm. The 150 sec. period includes an acceleration (2 to 4 inches Hg vacuum) from idle to 2000 rpm whereupon the engine speed is cycled every 20 seconds between 1800 and 2000 rpm with light accelerations (10 inches Hg vacuum) and closed throttle decelerated to idle and that deceleration time is included in the 40 sec. idle mode time. Airzfuel ratio is set for maximum power at idle and 14.0 i 0.5 for the higher speed accelerations.

The vehicle speed is controlled using throttle position and car speed commands from magnetic tape.

Intake air temperature is maintained at i 10F during the highspeed mode by drawing a portion of the intake flow over the exhaust manifold. All other engine temperatures are uncontrolled but water out averages 205 :1: 10F., and oil slump averages 220 1' 10F.

Blowby rate and pertinent temperatures are recorded each 8 hour period. The 60 hour period is equivalent to 2,500 miles of operation. At the end of 60 hours, the fuel supply is disconnected and the engine run out of fuel at 45 mph. The engine head is removed, inspected and with the valves in place, all head combustion chamber deposits brushed off. Valve positions are marked and valves subsequently removed. Valves, ports, manifold and carburetor throttle body are rated and piston top deposit condition noted. After the valves are photographed, they are weighed, cleaned and reweighed to obtain deposit weight.

The results obtained, employing the above-described test are shown in the following Table 11:

TABLE 11 Cone., Intake Valve Deposit Composition Wt. Avg. Wt. in Grams Base gasoline 0 1.088

do. Ex. 2 0.1 0.45

As will be seen from the foregoing comparative examples of Table II, a marked improvement in reduction of formation of carbonaceous surface deposits is obtained through the use of the above-described acetal.

In summary, from the comparative data of Tables I and II, it will be apparent that the above-described acetals of the present invention are effective in reducing formation of carbonaceous intake valve deposits from liquid hydrocarbon fuels in internal combustion engines and are also non-emulsive. It will be understood. of course, that the improved liquid'hydrocarbon fuel compositions of the present invention may also contain other additives such as antioxidants, detergents, dispersants, stability improvers and the like. It will also be understood that although the present invention has been described with preferred embodiments, various modifications and adaptations thereto may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand.

We claim:

A liquid hydrocarbon fuel containing a detergent improving amount of an acetal of a partial ester of an alcohol and an aldehyde, said ester having at least 18 carbon atoms.

2. A fuel as defined in claim 1 wherein said fuel comprises a petroleum distillate fuel.

3. A fuel as defined in claim 1 wherein said fuel has an initial boiling point of at least about 75F. and an end boiling point not higher than about 750F.

4. A fuel as defined in claim 1 wherein said fuel comprises a gasoline.

5. A fuel as defined in claim 1 wherein said fuel comprises a jet fuel. I I

6. A fuel as defined in claim 1 wherein said fuel comprises a diesel fuel.

7. A fuel as defin'ed in claim 1 wherein said acetal is present in an amount from about 0.001 to about 10%, by weight, of the total weight of said fuel.

8. A fuel as defined in claim I wherein said acetal is present in an amount from about 0.01 to about 0.5 percent, by weight, of the total weight of said fuel.

9. A fuel as defined in claim 1 wherein said acetal has the structure:

CHE-)0 Can Has CH3CH: a

10. A fuel as defined in claim 1 wherein said acetal has the structure: 

2. A fuel as defined in claim 1 wherein said fuel comprises a petroleum distillate fuel.
 3. A fuel as defined in claim 1 wherein said fuel has an initial boiling point of at least about 75*F. and an end boiling point not higher than about 750*F.
 4. A fuel as defined in claim 1 wherein said fuel comprises a gasoline.
 5. A fuel as defined in claim 1 wherein said fuel comprises a jet fuel.
 6. A fuel as defined in claim 1 wherein said fuel comprises a diesel fuel.
 7. A fuel as defined in claim 1 wherein said acetal is present in an amount from about 0.001 to about 10%, by weight, of the total weight of said fuel.
 8. A fuel as defined in claim 1 wherein said acetal is present in an amount from about 0.01 to about 0.5 percent, by weight, of the total weight of said fuel.
 9. A fuel as defined in claim 1 wherein said acetal has the structure:
 10. A fuel as defined in claim 1 wherein said acetal has the structure: 